Method of treating viscous liquids



R. RAFN. METHOD OF TREATING VISCOUS LIQUIDS.

APPLICATION FILED OCT. 15. 1918.

Patented Feb. 15, 1921.

ROBERT RAFN, OF MOSS, NORWAY.

METHOD OF' TREATING VISCOUS LIQUTDS.

Specification of Letters Patent.

Patented Feb. 15, 13:21,.

Application filed Qctober 15, 1918. Serial No. 258,252.

The invention relates to the treatment of.

liquids, which are of a viscous character such as for instance sweetened condensed milk and has for its object an improved method of effecting the cooling of such liquids.

When the viscous liquid is to be cooled and particularly when such liquids contain salts or other dissolved solid substances 1n a quantity near up to the saturation points, a very cautious treatment is necessary, which does not for instance by a local undercooling give rise to the formation of crystals and other inhomogenities in the body of liquid. Just as in the manufacture of several artificial emulsions this difficulty is encountered to a marked degree in the cooling of milk which has been concentrated with the usual high content of sugar, the apparatus employed to effect such cooling in a reliable manner being large and slowl operating and the process involving muc manual labor.

The apparatus which has hitherto been generally employed consists of a large cooling trough in which revolves a great number of pails provided with stationary stirrers. The milk is filled into all these pails, is cooled during several hours and is then again poured out. Each time of use of the pails necessitates complete cleaning of the whole of this large apparatus.

The present invention now has for its object a method whereby a continuous cooling without portioning the liquid and without manual labor is attained. According to this method the cooling takes place while the liquid is flowing in contact with cooling surfaces at the same time as the liquid is mechanically Worked by being rolled against cooling surfaces.

An embodiment of the apparatus employed for carrying this cooling method into effect is illustrated in the accompanying drawing, in which- Figure 1 is a longitudinal sectional view of the apparatus.

Fig. 2 is a transverse sectional view of the same.

In the illustrated example a sloping tubeshaped cooler 3 carrying a gear 7 revolves in a cooling jacket 1 in stufling boxes 2. The cooler tube is suitably made of copper or other heat conducting material. in the pipe is revolving a tinned shaft 4 being of such thickness as not to be bent during the working and being carried in ball bearings 5 suspended in such manner as to take up the axial pressure of the shaft in the direction of incline, while allowing it to rest with its own weight in the cooler tube. The shaft is in the illustrated example'made hollow as a pipe and is supplied with cooling water.

The inclination and the rotation velocity may be varied in accordance with the viscosity of the liquid. The cooling water enters at the lowest point of the cooling jacket through the inlet pipe 9, fills the jacket completely, washes around the cooler tube and leaves the jacket at the highest point through the pipe 10. The hot liquid flows through funnel 6 into the cooler at the upper end of the tube, flows down through this latter, gives off heat to the counter current of cooling water through the walls of the tube on its downward passage. During its passage through the cooler the liquid is kneaded and stirred by the rolling shaft. Toward the lower end of the tube, where the liquid in accordance as it is cooled, becomes more viscous, it will usually fill the tube so that in addition to its own weight and the action of the shaft also comes the pressure of a column of liquid, which acts to force the liquid forward to the lower end of the tube, where it is scraped off from the shaft by a knife 8 or the like.

The application of the counter current principle as well as the thorough agitation insures an ideal continuity of the cooling and prevents any sudden temperature changes in the liquid. It has been ascertained by experiments with a complete apparatus that the describedcombination of features results in a rapid, reliable cooling giving a homogeneous fine product.

Claims.

1. The method of treating viscous liquids which consists in causing the liquid to pass between surfaces which are maintained rolling upon one another under the-action of a yielding pressure and cooling the liquid during the passage.

2. The method of treating viscous liquids Which consists in passing the liquid over a cooling surface and subjecting it to the action of a roller during such passage.

3. The method of treating viscous liquids which consists in causing the liquid to repeatedly pass between surfaces which are maintained rolling upon another under the action of a yielding pressure and cooling the liquid during the passage.

4.7 The method of treating sweetened condensed milk which consists in passing the liquid over a cooling surface and subjecting it to the action of a roller during such passage. 7

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribin witnesses.

RO ERT RAFN. Witnesses:

M. W. KAHns, G. NORMAN. 

